// mcaptcha.js
 
export class Mcaptcha {
    constructor(options) {
      this.options = options;
      this.fontSize = options.height * 3 / 6;
      this.init();
      this.refresh();
    }
    init() {
      this.ctx = uni.createCanvasContext(this.options.el);
      this.ctx.setTextBaseline("middle");
      this.ctx.setFillStyle(this.randomColor(180, 240));
    }
    refresh() {
      var code = '';
      var txtArr = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q','r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',0,1,2,3,4,5,6,7,8,9]
      for(var i=0;i<4;i++){
        code += txtArr[this.randomNum(0, txtArr.length)];
      }
      this.options.createCodeImg = code;
      let arr = (code + '').split('');
      if (arr.length === 0) {
        arr = ['e', 'r', 'r','o','r'];
      };
      let offsetLeft = this.options.width * 0.6 / (arr.length - 1);
      let marginLeft = this.options.width * 0.2;
      arr.forEach((item, index) => {
        this.ctx.setFillStyle(this.randomColor(0, 180));
        let size = this.randomNum(24, this.fontSize);
        this.ctx.setFontSize(size);
        let dis = offsetLeft * index + marginLeft - size * 0.3;
        let deg = this.randomNum(-30, 30);
        this.ctx.translate(dis, this.options.height*0.5);
        this.ctx.rotate(deg * Math.PI / 180);
        this.ctx.fillText(item, 0, 0);
        this.ctx.rotate(-deg * Math.PI / 180);
        this.ctx.translate(-dis, -this.options.height * 0.5);
      })
      for (var i = 0; i < 4; i++) {
        this.ctx.strokeStyle = this.randomColor(40, 180);
        this.ctx.beginPath();
        this.ctx.moveTo(this.randomNum(0, this.options.width), this.randomNum(0, this.options.height));
        this.ctx.lineTo(this.randomNum(0, this.options.width), this.randomNum(0, this.options.height));
        this.ctx.stroke();
      }
      for (var i = 0; i < this.options.width / 4; i++) {
        this.ctx.fillStyle = this.randomColor(0, 255);
        this.ctx.beginPath();
        this.ctx.arc(this.randomNum(0, this.options.width), this.randomNum(0, this.options.height), 1, 0, 2 * Math.PI);
        this.ctx.fill();
      }
      this.ctx.draw();
    }
    validate(code){
      var code = code.toLowerCase();
      var v_code = this.options.createCodeImg.toLowerCase();
      console.log(code)
      console.log(v_code.substring(v_code.length - 4))
      if (code == v_code.substring(v_code.length - 4)) {
        return true;
      } else {
        return false;
      }
    }
    randomNum(min, max) {
      return Math.floor(Math.random() * (max - min) + min);
    }
    randomColor(min, max) {
      let r = this.randomNum(min, max);
      let g = this.randomNum(min, max);
      let b = this.randomNum(min, max);
      return "rgb(" + r + "," + g + "," + b + ")";
    }
  }